Assessment of low-scaling approximations to the equation of motion coupled-cluster singles and doubles equations

View/ Open
Issue Date
2014Author
Goings, Joshua J.
Caricato, Marco
Frisch, Michael J.
Li, Xiaosong
Publisher
American Meteorological Society
Type
Article
Article Version
Scholarly/refereed, publisher version
Rights
The following article appeared in Journal of Chemical Physics and may be found at http://scitation.aip.org/content/aip/journal/jcp/141/16/10.1063/1.4898709
Metadata
Show full item recordAbstract
Methods for fast and reliable computation of electronic excitation energies are in short supply, and little is known about their systematic performance. This work reports a comparison of several low-scaling approximations to the equation of motion coupled cluster singles and doubles (EOM–CCSD) and linear-response coupled cluster singles and doubles (LR–CCSD) equations with other single reference methods for computing the vertical electronic transition energies of 11 small organic molecules. The methods, including second order equation-of-motion many-body perturbation theory (EOM–MBPT2) and its partitioned variant, are compared to several valence and Rydberg singlet states. We find that the EOM–MBPT2 method was rarely more than a tenth of an eV from EOM–CCSD calculated energies, yet demonstrates a performance gain of nearly 30%. The partitioned equation-of-motion approach, P–EOM–MBPT2, which is an order of magnitude faster than EOM–CCSD, outperforms the CIS(D) and CC2 in the description of Rydberg states. CC2, on the other hand, excels at describing valence states where P–EOM–MBPT2 does not. The difference between the CC2 and P–EOM–MBPT2 can ultimately be traced back to how each method approximates EOM–CCSD and LR–CCSD. The results suggest that CC2 and P–EOM–MBPT2 are complementary: CC2 is best suited for the description of valence states while P–EOM–MBPT2 proves to be a superior O(N5) method for the description of Rydberg states.
Collections
Citation
Goings, J. J., Caricato, M., Frisch, M. J., & Li, X. (2014). Assessment of low-scaling approximations to the equation of motion coupled-cluster singles and doubles equations. The Journal of chemical physics, 141(16), 164116.
Items in KU ScholarWorks are protected by copyright, with all rights reserved, unless otherwise indicated.
We want to hear from you! Please share your stories about how Open Access to this item benefits YOU.